Etanercept normalizes systemic bone metabolism in rheumatoid arthritis patients.

초록

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease accompanied by bone loss. Etanercept is soluble TNF-α receptor which is effective in suppressing RA activity. Objective: Our aim is to assess bone metabolism in TNF naïve RA patients and to figure out effects of etanercept on bone turnover markers and inflammatory mediators. Methods: Twenty-one RA patients (19 women and 2 men; age 46.29 ± 11.6 years) were included. Age and sex matched control group were recruited. Etanercept was administered at standard dose, twice a week. Venous blood was drawn at baseline in both groups and at week 14-16 after etanercept use in RA patient. Differences between two groups were examined for statistical difference by Wilkoxon signed ranks test. A p value of less than 0.05 was denoted statistically significant. Results: At baseline the sclerostin level was significantly decreased in RA patients than in control group while serum CTX was decreasing. However after etanercept use, both serum CTX and sclerostin markedly increased (Table 1). BSAP and OPG were slightly affected by etanercept. RANKL mildly decreased after treatment. Inflammatory mediators responded to the treatment as ESR, CRP and IL-6 all significantly decreased (Table 2). Conclusions: Our study showed lower level of serum CTX and sclerostin in RA patients than in control group, which suggested slow bone resorption rate coupled with low bone production. However after etanercept use, bone turnover markers rose while inflammation was decreasing. Therefore we conclude that etanercept stimulates depressed bone metabolism in RA patients as it suppresses inflammation.